1. Field of the Invention
The present invention relates to proppant storage containers. More particularly, the present invention relates to systems and methods for the delivery of proppant to a well site. More particularly, the present invention relates to containers as part of a system of storing proppant prior to delivery to a well site.
2. Description of Related Art
Hydraulic fracturing is the propagation of fractions in a rock layer caused by the presence of pressurized fluid. Hydraulic fractures may form naturally, in the case of veins or dikes, or may be man-made in order to release petroleum, natural gas, coal seam gas, or other substances for extraction. Fracturing is done from a wellbore drilled into reservoir rock formations. The energy from the injection of a highly-pressurized fracturing fluid creates new channels in the rock which can increase the extraction rates and ultimate recovery of fossil fuels. The fracture width is typically maintained after the injection by introducing a proppant into the injected fluid. Proppant is a material, such as grains of sand, ceramic, or other particulates, that prevent the fractures from closing when the injection is stopped.
With the rise of hydraulic fracturing over the past decade, there is a steep climb in proppant demand. Global supplies are currently tight. The number of proppant suppliers worldwide has increased since 2000 from a handful to well over fifty sand, ceramic proppant and resin-coat producers.
By the far the dominant proppant is silica sand, made up of ancient weathered quartz, the most common mineral in the Earth's continental crust. Unlike common sand, which often feels gritty when rubbed between the fingers, sand used as a proppant tends to roll to the touch as a result of its round, spherical shape and tightly-graded particle distribution. Sand quality is a function of both deposit and processing. Grain size is critical, as any given proppant must reliably fall within certain mesh ranges, subject to downhole conditions and completion design. Generally, coarser proppant allows the higher flow capacity due to the larger pore spaces between grains. However, it may break down or crush more readily under stress due to the relatively fewer grain-to-grain contact points to bear the stress often incurred in deep oil- and gas-bearing formations.
Typically, in any hydraulic fracturing operation, a large amount of such proppant is required. Typically, it has been difficult to effectively store the proppant at the fracturing sites. Additionally, it has been found to be rather difficult to effectively transport the proppant to the desired location. Often, proppant is hauled to the desired locations on the back of trucks and is dumped onsite. Under such circumstances, the proppant is often exposed to adverse weather conditions. This will effectively degrade the quality of the proppant during its storage. Additionally, the maintenance of proppant in containers at the hydraulic fracturing site requires a large capital investment in storage facilities. Typically, the unloading of such storage facilities is carried out on a facility-by-facility basis. As such, there is a need to be able to effectively transport the proppant to and store the proppant in a desired location adjacent to the hydraulic fracturing location.
Present methods of storing proppant for use at the well site has involved a significant investment in structural facilities. In particular, silos have been built in order to store proppant for use in the fracturing operation. Often, the silos can have a cost of several million dollars. Whenever such silos are used, there is a possibility of contamination of the proppant that is contained within the silo. Large storage facilities often mix various types and qualities of proppant. As such, lower quality proppant may be mixed with higher quality proppant so as to create an undesirable contaminated combination.
The availability of high quality proppant is always of a major concern during such fracturing operations. If the proppant is not available at the well site, then the fracturing operation can stall until such time that proppant is available. In other circumstances, the operators of the fracturing operation may be forced to use lower quality proppant in order to continue the operation. As such, there is a need to be able to have high quality proppant available at all times during the fracturing operation. It is also advantageous to provide a system which avoids the mixture of different types of proppant and to avoid the contamination of the proppant supply.
Under certain circumstances, railcars are used to deliver proppant to the fracturing location. The proppant is unloaded from the railcars into pneumatic bulk trailers. The pneumatic bulk trailers can then deliver the proppant to the well site. Often, the bulk materials train will have to remain on-site during the time the proppant remains in the bulk material train. As such, the train is not able to be used for other purposes. This adds additional cost to the fracturing operation. Ultimately, after the train is completely unloaded, a new bulk material train must be transported to the desired location and then serve as a storage facility. As such, a need is developed so as to quickly remove all of the proppant from the bulk material train and to store such proppant until such time as the proppant is needed.
In the past, various patents have issued relating to storage and transport facilities. For example, U.S. Patent Publication No. 2008/0179054, published on Jul. 31, 2008 to McGough et al., shows a bulk material storage and transportation system. In particular, the storage system is mounted on the trailer of a truck. The storage system includes walls that define an interior volume suitable for receiving the aggregate material therein. There are hoppers provided at the bottom of the container. These hoppers have inclined walls. The hoppers can extend so as to allow the material from the inside of the container to be properly conveyed to a location exterior of the container. Actuators are used so as to expand and collapse the container.
U.S. Pat. No. 7,240,681, issued on Jul. 10, 2007 to L. Saik, describes a trailer-mounted mobile apparatus for dewatering and recovering formation sand. The trailer is mounted to a truck-towable trailer so as to receive sand therein. The container has a pair of sloping end walls. The back end of the container is suitably openable so as to allow the sand to be removed therefrom. A pneumatic or hydraulic ram is provided on the forward part of the container so as to allow the container to be lifted angularly upwardly so as to allow sand to be discharged through the gate at the rear of the container.
U.S. Pat. No. 4,247,228, issued on Jan. 27, 1981 to Gray et al., describes a dump truck or trailer with a pneumatic conveyor. The container is mounted to a frame on wheels. A hydraulic ram tilts the container for dumping through a rear outlet. A pneumatic conveyor is carried by the frame with an intake at the rear of the container. A gate allows the solids to be dumped conventionally by gravity or to be blown to a storage facility by the pneumatic container. The container has a top hatch formed therein so as to allow the solids to be introduced into the interior of the container.
U.S. Pat. No. 2,865,521, issued on Dec. 23, 1958 to Fisher et al., shows a bulk material truck that has an interior volume suitable for the receipt of bulk material therein. A pneumatic conveyer is utilized so as to allow the removal of such material from the bottom of the container. A pair of sloping walls are provided on opposite sides of the container so as to allow the bulk material within the container to be passed toward the bottom of the container. A top hatch is provided on the top of the conveyer. The pneumatic conveyer is connected to the bottom of the container.
U.S. Pat. No. 4,995,522, issued on Feb. 26, 1991, to F. M. Barr, describes a bottom dumping bulk container apparatus for a bulk granulated material. The shipping container has a lower wall with a discharge opening. Doors are provided for the opening and closing of the discharge opening. The doors are actuated by an actuating structure which is mounted for vertical movement relative to the container. The actuating structure has upper portions which serve as conventional lifting connectors or receptacles at corners of the container. These cooperate with conventional hooks so that raising the actuating structure opens the door and lowering the actuating structure closes the door. This permits granulated material within the container to be dumped into a lower container or conveyance without requiring specialized lifting or opening equipment.
U.S. Pat. No. 6,401,983, issued on Jun. 11, 2002 to McDonald et al., provides a bulk cargo container for storing and transporting solid and liquid bulk materials. The bulk cargo container includes a vessel suitable for containing the bulk material and a supporting frame assembly having a generally horizontally-disposed support member attachment. The container portion is formed into at least one hopper having a discharge opening therein suitable for discharging bulk material contained within the vessel.
U.S. Pat. No. 4,138,163, issued on Feb. 6, 1979 to Calvert et al., discloses a bulk material container for the handling of flowable particulate materials. This container has a closed, generally rectangular parallelpiped structure with side walls, end walls and a roof. Conduits permit the introduction and withdrawal of particulate material to and from the container body. The lower base portion supports a vertical flexure panel at each corner thereof. The vertical flexure panel supports opposed pairs of longitudinal and transverse flexure panels between the tops thereof.
U.S. Pat. No. 4,909,556, issued on Mar. 20, 1990 to T. Koskinen, provides a transport container for the transport of bulk material. This transport container has a filling-hole in the upper part and an emptying device in the rear. For the loading and unloading, a side section is provided that can be opened. An emptying device, in the nature of a pneumatic pressure discharger, allows the material to freely flow from the containers through a check valve.
U.S. Pat. No. 7,967,161, issued on Jun. 28, 2011 to A. M. Townsend, provides a shipping container liner system for the shipping of bulk flowable materials. The system has a specially-adapted shipping container liner that is self-supporting without the need for rear-mounted rigid supportive bars to retain the liner within the shipping container during filling and discharge. The system has an arrangement of interior support baffles operating in conjunction with a plurality of exterior anchor straps adapted to distribute the cargo load throughout the length of the container.
U.S. Pat. No. 5,690,466, issued on Nov. 25, 1997 to Gaddis et al., shows slope plate for a particulate material truck box. The slope plate assembly includes a plurality of slope plate sections pivotally connected to the opposite side walls of the truck box so as to be movable between a raised inoperative position and a lowered operative position. In the lowered position, particulate material flows by gravity along the slope plate sections for discharge into an auger assembly residing below the floor of the truck box. In the raised position, bulk material or other cargo can be loaded into the truck box.
It is the object of the present invention to provide a system for the storage and transport of proppant that is mobile, scalable and flexible.
Another object to the present invention to provide a system for the storage and transport of proppant that can be located in proximity to the rail spur.
Another object of the present invention to provide a system for the transport and storage of proppant that can be rapidly implemented.
Another object of the present invention to provide a system for the storage and transport of proppant that occupies a small footprint.
The further object of the present invention to provide a system for the storage and transport of proppant that assures a continuous inventory of proppant to the fracturing operation.
Still another object of the present invention is to provide a system for the storage and transport of proppant that is movable and rechargeable at the drill site.
The further object of the present invention is to provide a system for the storage and transport of proppant that enhances the productivity of the proppant supplier.
The further object of the present invention to provide a system for the storage and transport of proppant that reduces driver fatigue.
Another object of the present invention to provide a system for the storage and transport of proppant that reduces liabilities.
The further object of the present invention to provide a system for the storage and transport of proppant that improves safety.
Further object of the present invention to provide a system for the storage and transport of proppant that is compliant with Department of Transportation regulations.
Still another object of the present invention to provide a system for the storage and transport of proppant which improves the profits for the proppant supplier.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.